case *syntax.ExprStmt:
		// spec: "With the exception of specific built-in functions,
		// function and method calls and receive operations can appear
		// in statement context. Such statements may be parenthesized."
		var x operand
		kind := check.rawExpr(nil, &x, s.X, nil, false)
		var msg string
		var code Code
		switch x.mode {
		default:
			if kind == statement {
				return
			}

	case *ast.ExprStmt:
		// spec: "With the exception of specific built-in functions,
		// function and method calls and receive operations can appear
		// in statement context. Such statements may be parenthesized."
		var x operand
		kind := check.rawExpr(nil, &x, s.X, nil, false)
		var msg string
		var code Code
		switch x.mode {
		default:
			if kind == statement {
				return
			}

	// This test checks nextStdChunk's behavior directly,
	// instead of needing to test it only indirectly through Parse/Format.

	// markChunks returns format with each detected
	// 'format chunk' parenthesized.
	// For example showChunks("2006-01-02") == "(2006)-(01)-(02)".
	markChunks := func(format string) string {
		// Note that NextStdChunk and StdChunkNames
		// are not part of time's public API.

 * side, this yields nine basic types of ranges, enumerated below. (Notation: a square bracket
 * ({@code [ ]}) indicates that the range is closed on that side; a parenthesis ({@code ( )}) means
 * it is either open or unbounded. The construct {@code {x | statement}} is read "the set of all
 * <i>x</i> such that <i>statement</i>.")
 *
 * <blockquote>
 *
 * <table>

 * side, this yields nine basic types of ranges, enumerated below. (Notation: a square bracket
 * ({@code [ ]}) indicates that the range is closed on that side; a parenthesis ({@code ( )}) means
 * it is either open or unbounded. The construct {@code {x | statement}} is read "the set of all
 * <i>x</i> such that <i>statement</i>.")
 *
 * <blockquote>
 *
 * <table>

		// digits?
		for s.accept(decimalDigits + "_") {
		}
	}
	return string(s.buf)
}

// complexTokens returns the real and imaginary parts of the complex number starting here.
// The number might be parenthesized and has the format (N+Ni) where N is a floating-point
// number and there are no spaces within.
func (s *ss) complexTokens() (real, imag string) {
	// TODO: accept N and Ni independently?
	parens := s.accept("(")

	case *parse.ChainNode:
		return s.evalChainNode(dot, n, cmd.Args, final)
	case *parse.IdentifierNode:
		// Must be a function.
		return s.evalFunction(dot, n, cmd, cmd.Args, final)
	case *parse.PipeNode:
		// Parenthesized pipeline. The arguments are all inside the pipeline; final must be absent.
		s.notAFunction(cmd.Args, final)
		return s.evalPipeline(dot, n)
	case *parse.VariableNode:
		return s.evalVariableNode(dot, n, cmd.Args, final)